For example, on a CD (compact disc) that conforms to the CD-TEXT format, character data for presenting the title of music recorded on each track, artist name, etc. for display on an operation panel is recorded in addition to the audio playback digital data recorded on conventional CD.
Such character data can be written by a user using a CD-R writer. However, when character data is written to a CD by using a CD-R writer, there can occur cases where data that does not conform to the standard is written due to errors on the part of the user. If such data is to be displayed as is, totally unintelligible characters may be displayed. Further, there can occur cases where a null code indicating a track separation cannot be detected and, as a result, the character data acquisition process does not terminate, endlessly trying to acquire the character data and thus resulting in an inability to proceed to the audio playback process.